This invention relates to a passive vehicle occupant restraint belt system in which the belt is automatically, easily and effectively transferred between an occupant-restraining and an occupant-releasing configuration in response to opening and closing movements of a vehicle door.
In recent years, there have been many proposals for passive occupant restraint systems for vehicles. The most common types of restraint systems are those based on restraint belts, and most of the proposed passive belt systems include a belt transfer mechanism which is driven by an electric motor or a mechanical lever or gear transmission. In the case of mechanical drives, a motion transmitting device is coupled between the belt transfer device and the vehicle or door for transmitting and amplyifying the door opening and closing movements. One such mechanical device, which is capable of moving the restraint belt from an occupant-restraining to the occupant-releasing position in response to the partial opening of the door is shown and described in commonly-owned U.S. patent application Ser. No. 950,020 filed Oct. 10, 1978.
In operation, when a vehicle occupant opens the door, the belt is automatically moved from its restraining to its releasing position and the passenger is free to get out of the vehicle. Correspondingly, when the door is closed, the belt moves back to its occupant-restraining position. The back and forth movement of the belt occurs every time the door is opened and closed, whether or not there is a passenger occupying the seat at the time. When a passenger leaves the vehicle and closes the door, the system functions, even though there is no occupant. This means, in fact, that about one-half of the operating cycles are unnecessary.